1. Field of the Invention
The invention relates to a steering system.
2. Description of the Related Art
A steering column described in U.S. Patent Application No. 2009/0013817 (US 2009/0013817 A) includes an adjustment portion and a holding portion that is fixed in position in an adjustment direction. The adjustment portion can adjust the position of the steering column. The holding portion does not move in an adjustment direction for the steering column in accordance with the positional adjustment of the steering column. To the adjustment portion, a jacket unit is attached which holds the steering shaft. A slot formed in the holding portion extends along the adjustment direction. Teeth aligned along the adjustment direction are provided on the holding portion. A clamp bolt inserted through the slot in the holding portion penetrates a tooth plate. The tooth plate has teeth aligned in the adjustment direction.
Operating an operation member attached to the clamp bolt enables a pressing member through which the clamp bolt is inserted to be moved toward the holding portion. Moving the pressing member toward the holding portion allows the tooth plate to be pressed by the pressing member and moved toward the holding portion. At that time, the tooth portions of the tooth plate move into spaces between the tooth portions of the holding portion and mesh with the tooth portions of the holding portion. Consequently, the jacket unit is fixed in position in the adjustment direction.
In the steering column in US 2009/0013817 A, the adjustment direction is a direction along a circular arc around a turning shaft provided in a bracket fixed to a chassis of the vehicle, that is, what is called a tilt direction. A distance between the turning shaft and the slot is set according to a vehicle type. Thus, even a slight difference in the distance according to the vehicle type leads to a change in the curvature of the circular arc. The change in the curvature of the circular arc requires changing not only the shape of the slot in the holding portion but also the shape and pitch of the tooth portions aligned in the holding portion and the tooth plate along the adjustment direction. This hinders the use of a common configuration adapted to fix the column jacket in position in the adjustment direction by meshing the teeth with one another.